By Owen Bennett-Jones
6 April 2016
The group that carried out the Lahore attack afterwards released a photograph of the suicide bomber. Predictably enough he looks young, 21 maybe. It's a heavily posed shot - he's on his haunches with a huge gun behind him and his right hand is raised in front of his face with his forefinger extended as if he was emphasising a point. "Listen!" he seems to be saying. "Just listen to me!"
And once again the question that demands an answer: what on Earth was he thinking? A few months ago I met a young man in Lahore, Khalid Mehmood, who volunteered to join a group of Islamist militants - and started a journey that for some ends up with a clenched fist, a triggered detonator and mayhem. He didn't go that far, but still, why did he think violent jihad was right for him?
There was a school in Khalid Mehmood's village but he didn't go. Instead he worked with his father, sowing crops and watering them. Then, like many adolescents, he wanted to fly the nest. At the age of 12 he went to Lahore and started working in a factory. One day - he was 15 by this point - Khalid thought that he would like to see a film. He had never see one before and he thought the time had come to go to a cinema.
As he walked through Lahore he got diverted by a rally. This was a fair while ago now - in the months after 9/11 - and emotions were running high. It turned out the rally was organised by one of Pakistan's most formidable militant outfits, Jaish-e-Mohammad, and everyone was chanting anti-American slogans. There were announcements saying: "We need people to go to Afghanistan to fight the Americans!"
Khalid volunteered on the spot. "I thought, 'I can go to see another country'," he said. In no time at all he'd been driven to Kandahar, the Taliban stronghold in southern Afghanistan.
It was then he realised how little he knew about religion.
"I had never really said any prayers in Pakistan. I never knew the right words," he told me.
An Afghan cleric taught him how to pray - there was no instruction in violent jihad. But still, life was difficult, Khalid said. "They were all Pashtuns and I could not understand their language. I was in another world," he told me. "There were bullets flying around. I wanted to go back home."
But he hardly knew where he was, so there was no chance of his returning to Pakistan on his own.
After 15 days he was moved up to northern Afghanistan where the Taliban were fighting and where he attended to wounded fighters. But the Taliban were soon in retreat and Khalid and some others from Pakistan were told they could go back home. They started out in buses but, after being relieved of their vehicles at a checkpoint, had to continue on foot.
After a few hours walking they were picked up by one of Afghanistan's most notorious warlords who told the Pakistanis to get in a container that would take them back to their country. Those who refused to get in were shot. Crammed in, the men began to panic and fight. Khalid fainted - and it probably saved his life.
He later learned that while he was unconscious the warlord's men walked around the outside of the container firing bullets into it. Khalid was one of only 15 or 16 to get out alive.
The dead bodies of the others were thrown out into the desert, doused in petrol and burned.
Khalid was taken to a compound in the nearby town of Mazar-e-Sharif. But there was no food and hardly even a glass of water. The prisoners protested saying: "Either kill us or set us free." Eventually they were moved on… to a prison in Kabul.
After six months there the Pakistani ambassador intervened and got 40 to 50 prisoners sent back home. But Khalid still wasn't a free man. For nearly a year he was moved from prison to prison in Pakistan before, eventually, he was released.
At last he was able to get back home.
"It was really nice," he said. "I felt I was in heaven. My family got me married and I found a new job. I am happy now."
So how does he look back on those momentous events?
"I was inexperienced," he said. "I first stated working in a factory when I was 12. I just went to see another country. It seemed exciting. But it was a total disaster."
And that's the story of Khalid Mehmood - and what happened when, one day, he thought it would be fun to watch a movie.